Joint Exercises at Trincomalee (JET) started in 1950 and were organised at Trincomalee on the East coast of Ceylon. Initially, JETs were held in the spring. Later, JETs were held during the height of the Southwest monsoon when the West coast of India became unsuitable for naval exercises due to rain and rough seas. Trincomalee and the exercise areas in the vicinity were sheltered from the monsoon and provided calm seas. Ships of Commonwealth navies participated in JET, which were held under the general guidance and control of the Royal Navy Commander in Chief of Far East Fleet, using the facilities available at Trincomalee.
The pattern was for individual ships to shake down, followed by each Commonwealth Navy working up its ships and culminating in Joint Exercises in the Bay of Bengal. The combined exercises lasted for a period of two weeks during which a variety of exercises were carried out, including gunnery firing practices at surface and aerial targets, anti submarine exercises with British submarines as targets, replenishment at sea with British tankers, ship manoeuvres and culminating in large scale tactical exercises. The basic advantage of these exercises was the exposure to contemporary tactics and cross-operating with other navies. The Ariel photos were taken in February 1960 by the pilot of an aircraft attached to carrier HMS Centaur, which is anchored at the background of the following image. HMS Belfast is in the foreground.